Medicament delivery device

ABSTRACT

A medicament delivery device includes a housing having a proximal housing part and a distal housing part movable relative each other, a drive force mechanism accommodated in the distal housing part, a container filled with medicament arranged within the proximal housing part, a holding member for holding the drive force mechanism in a loaded state, and an actuation member arranged to interact with the holding member for releasing the drive force mechanism from its loaded state. The holding member is arranged to be moved from a disengaged position, in which the holding member is disengaged from the actuation member, to an engaged position, in which the holding member is engaged to the actuation member by moving the housing parts in relation to each other.

This application is a national stage entry of PCT/SE2011/051012, whichclaims priority from U.S. Provisional Applications No. 61/378,603 filedAug. 31, 2010 and No. 61/380,291 filed Sep. 6, 2010.

TECHNICAL FIELD

The present invention relates to a medicament delivery device foradministering, dispensing or delivering medicaments in a safe andreliable way. More particularly, it relates to an injection device formanually penetrating a needle arranged to said device and automaticallyinjecting a drug mixture from a multiple chamber container

BACKGROUND OF THE INVENTION

There are different types of medicaments that can be stored for a longtime and that are filled in containers e.g. cartridges, syringes,ampoules, canisters or the like, containing a ready-to-use medicament inliquid state. However, there are also other types of medicaments thatare a mixture of two substances, a medicament agent (e.g. lyophilized,powdered or concentrated liquid) and a diluent (e.g. water, dextroxsolution or saline solution), wherein these types of medicaments cannotbe pre-mixed and stored for a long time because the medicament agent isunstable and can be degraded and loses its effect quickly. Hence, auser, e.g. a patient himself/herself, a physician, a nurse, hospitalpersonnel or trained persons, has/have to perform the mixing within alimited time period prior to the delivery of a dose of medicament to apatient. Further, some medicament agents are subject to meet significantchemical changes while mixing. Such sensitive medicament agents requirea particular treatment so that, when mixing said medicament agents witha diluent, unreasonable mixing force will degrade said medicamentagents.

In order to facilitate the mixing, a number of containers for mixinghave been developed comprising at least two chambers, known asmulti-chamber containers. These multi-chambered containers comprise afirst chamber containing the medicament agent and at least a secondchamber containing the diluent. These chambers are sealed off withstoppers such/so that the medicament agents do not become degraded. Whenthe medicament agent is to be mixed shortly before administering,redirecting passages are opened between the chambers, usually bydepressing a distal stopper and in turn a divider stopper of thecontainer somewhat.

The passages allow the mixing of the medicament agent and the diluentand the medicament is ready for delivery.

The above mentioned requirements can be achieved by simple medicamentdelivery devices, such as a common hypodermic syringe, but the procedureis of course rather awkward, in particular for users not used to handlethese devices. In order to facilitate for the patients themselves toadminister the medicament with a predetermined dose in an easy, safe andreliable way and also to facilitate the administration of medicamentsfor hospital personnel in the same facilitated way, a number ofautomatic and semi-automatic devices have been developed in combinationwith these multiple-chamber solutions for obtaining a mixing beforedelivery.

A self-injection device arranged with a dual-chamber container, whereinboth the mixing and the injection are done automatically by mechanicalmeans, as springs and other means, is disclosed in U.S. Pat. No.4,755,169. A similar solution is disclosed in U.S. Pat. No. 6,793,646wherein the mixing of a dual-chamber cartridge is done automatically bysprings upon activation of the device and the injection is done bymanually applying a force to a plunger rod forwardly. A drawback withthese devices is that the mixing force, to which medicament agents aresubject to, is too high at the beginning due to Hookes law. Hence, themedicament agents can be degraded.

Another solution is disclosed in WO 2004004809, wherein both the mixingand the injection are done automatically by electronically controlledmeans. A drawback with this device is that the electronics are dependenton batteries and is very sensitive to noise, moisture, water, etc.;which can result in malfunctions. Also the manufacture of these devicesis more expensive than the manufacture of mechanical devices.

In U.S. Pat. No. 6,319,225 the mixing of a dual-chamber ampoule is donemanually. The device is set to be vertical on a flat plane and then adownward press on its proximal case causes a relative upward movement ofits plunger rod pressing a stopper of the ampoule with eye observationon actions inside the ampoule, such that a mixing is obtained. Though inU.S. Pat. No. 6,319,225 is disclosed that the best suitable process formixing a medicament agent with a diluent, is by performing manualcontrol of the diluent flow with adequate slowness which will bemonitored by eye observation; a drawback with this device is that themixing force, to which medicament agents are subject to, can be high ifthe user is stressed and wants to use the device as soon as possible.Hence, the medicament agents can be degraded.

Moreover, the handling and safety aspects of injector devices, having acertain degree of automatic functions, as well as immediateaccessibility in emergency situations are issues that attract a lot ofattention when developing this type of devices.

One important safety aspect when handling an auto-injector which is usedto achieve a manual mixing and an automatic injection, is the locking ofthe injection means, e.g. a compressed spring arranged to drive aplunger rod, before the manual mixing has been completed.

One such device is disclosed in U.S. Pat. No. 6,893,420 wherein aself-injection device is arranged with a dual-chamber body. The mixingis done manually by a screw-tightening operation and the devicecomprises locking means for locking a latch means that prevent theautomatic penetration and injection means from being released before themixing has been completely finished. However, this solution is ratherbulky and relies also on many components acting in co-operation and insequence, one triggering another, which may lead to a mal-function,mal-dose accuracy, or that the device becomes complicated, hence notuser friendly. This device suffers from the drawback that locking meanshas to be actively removed from the device after the mixing has beenfinished. This is a step which is not intuitive for a user, who will tryto push the locking means instead of removing them. Another drawback isthe dose accuracy, since the penetration starts pushing the stoppers,the medicament will be expelled during the whole penetration sequence,leading to so called wet injections and delivery of medicament throughthe whole penetration sequence instead of injecting the required dose atthe intended penetration depth.

Another such a device is disclosed in WO2007/115424A1 which relates toan injection device having a container holder having a multi-chambercontainer within, which is manually movable relative to the injectiondevice for the purpose of mixing the components within the multi-chambercontainer. The device further comprises a spring which can bear on apart of the injection device, and a coupling element for coupling thecontainer holder to the spring such that, during the movement of thecontainer holder into the injection device, the spring is tensioned. Thedevice also comprises an activation knob and a push button, wherein theactivation knob has to be rotated for forcing the push button toprotrude from the housing and thereby setting the device in a ready forinjection delivery state. However, this solution suffers from thedrawback that the activation knob has to be actively manipulated forreleasing the push button after the mixing has been finished. This is astep which is not intuitive for a user, who will try to find where thepush button or activation means are located instead of rotating theknob.

Moreover, another device disclosed in WO2009/147026A1, which is anearlier patent application of the present applicant, suffers from theproblem of not indicating to the user when the auto-injection hasstarted and also when the auto-injection is finished.

Even though the devices according to U.S. Pat. No. 6,893,420,WO2007/115424A and WO2009/147026A1 have proved to function well anddisplay a degree of safety, there is always a desire for improvements ofsuch devices, among them being the design of the mechanism in order tosimplify the manufacture and assembly in order to reduce costs but atthe same time having improved features maintaining or even improving thereliability of the safety and function of the device.

BRIEF DESCRIPTION OF THE INVENTION

The aim of the present invention is to provide an improved medicamentdelivery device capable of handling medicament delivery in a safe andreliable way wherein the risk of accidental premature firing of thedevice is precluded or minimised.

This aim is obtained according to a main aspect of the invention by amedicament delivery device according to the independent patent claims.Preferable details of the technical and/or functional features of theinvention form the subject of the dependent patent claims.

According to a main aspect of the invention, it is characterised by amedicament delivery device comprising a housing, which housing comprisesa proximal housing part and a distal housing part arranged and mountedto be movable relative each other, a drive force mechanism accommodatedin said distal housing part and comprising counter connecting means, acontainer filled with medicament arranged within said proximal housingpart, a holding member operably connected to said drive force mechanismfor holding said drive force mechanism in a loaded state and whereinsaid holding member comprises connecting means and engagement means, anactuation member (56) arranged to interact with said holding member forreleasing the drive force mechanism from its loaded state and whereinsaid actuation member comprises counter engagement means, wherein saidholding member is arranged to be moved by the proximal housing part whensaid housing parts are moved towards each other from a disengagedposition in which the holding member is disengaged from the actuationmember to an engaged position in which the holding member is engaged tothe actuation member, such that the engagement means of the holdingmember and the counter engagement means of the actuation member interacttogether for engaging the connecting means of the actuation member tothe counter connecting means of the drive force mechanism.

According to another aspect of the invention, the proximal housing partcomprises a co-acting means and the holding member comprises a counterco-acting means which interact together for moving the holding memberfrom the disengaged position to the engaged position.

According to a further aspect of the invention, the actuation membercomprises a touchable part that protrudes from the distal housing partand wherein said actuation member is resiliently arranged to said distalhousing part such that the actuation member in the disengaged positionof the holding member can be moved relative to the distal housing partwithout acting on said drive force mechanism.

According to yet a further aspect of the invention, the drive forcemechanism comprises a plunger rod, a drive force spring and a drivemember.

According to another aspect of the invention, the drive member comprisesreleasable means and the plunger rod comprises counter releasable meanswhich interact together for releasably engaging the plunger rod to thedrive member.

According to yet another aspect of the invention, the releasable meansof the drive member are radially flexing arms provided with inwardlyextending ledges and the counter releasable means of the plunger rod isa groove on its circumferential surface, wherein the inwardly extendingledges fit into said groove, and wherein the holding member is arrangedcompletely surrounding the radially flexing arms when said holdingmember is in the disengaged position.

According to a further aspect of the invention, the co-acting means ofthe proximal housing part is a distal end annular surface of theproximal housing part and the counter co-acting means of the holdingmember is an annular ledge on the outer circumference of the holdingmember.

According to yet a further aspect of the invention, the engagement meansof the holding member are distally extending tongues and the counterengagement means of the actuation member are proximally extendingflexible tongues.

According to another aspect of the invention, the connecting means ofthe actuation member are radial inwardly extending protrusions on theproximally extending flexible tongues of the actuation member and thecounter connecting means of the drive force mechanism are recesses onthe distal outer surface of the drive member, such that said recessesare configured to receive said radial inwardly extending protrusions.

According to yet another aspect of the invention, the holding member ismoved by said proximal housing part from the disengaged position to theengaged position in which the holding member is partially surroundingthe radially flexing arms and is engaged to the actuation member.

According to a further aspect of the invention, the container is amulti-chamber medicament container and whereby the multi-chamber can bemixed by moving said housing parts in relation to each other.

According to yet a further aspect of the invention, the engaged positionof the holding member corresponds to a position of the multi-chamber, inwhich the multi-chamber is mixed.

There are a number of advantages with the medicament delivery deviceaccording to the present invention. The fact that the actuation memberand the holding member are disengaged from each other when the twohousing parts are in an initial position relative each other ensuresthat the device cannot be activated accidentally, i.e. it requires anactive action by a user in order to activate the device. The activationis performed by moving the housing parts in relation to each other, morepreferably towards each other along the longitudinal axis of the device.According to an aspect of the invention this activation is performed byrotating the housing parts in relation to each other, which is anintuitive operation. Preferably the housing parts are threadedlyconnected to each other whereby one housing part is moved into theother.

During the movement of the housing parts the actuation member is stilldisconnected from the holding member and thereby disengaged from thedrive force mechanism and thus no activation may be performed. Onlyafter the two housing parts are completely moved in relation to eachother such that the holding member is operably interacting with theactuation member for engaging the actuation member to the drive forcemechanism, more preferably to the drive member, it is possible toperform a dose delivery from the medicament container. In that respect,the medicament container is preferably a multi-chamber container,whereby the activation, i.e. moving of the housing parts, causes adistal stopper of the multi-chamber container to be pressed against theproximal end of the plunger rod wherein a mixing of the componentswithin the container is performed.

In all a simple and reliable device capable of handling alsomulti-chamber medicament containers is obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed description of the invention, reference willbe made to the accompanying drawings, of which

FIG. 1 is a side view of an embodiment of the invention in an initialposition,

FIG. 2 is a cross-sectional side view of the device of FIG. 1,

FIG. 3 is a detailed view taken from the area III of FIG. 2, and

FIGS. 4 to 7 are cross-sectional views of the device of FIG. 1 indifferent functional positions.

DETAILED DESCRIPTION OF THE INVENTION

In the present application, when the term “distal part/end” is used,this refers to the part/end of the delivery device, or the parts/ends ofthe members thereof, which is/are located the furthest away from themedicament delivery site of the patient. Correspondingly, when the term“proximal part/end” is used, this refers to the part/end of the deliverydevice, or the parts/ends of the members thereof, which, is/are locatedclosest to the medicament delivery site of the patient.

The present invention relates to a medicament delivery device comprisinga housing, more preferably a generally elongated housing extending alonga longitudinal axis of the device, which housing comprises a proximalhousing part 12 and a distal housing part 10 arranged and mounted to bemovable relative each other along the longitudinal axis of the device, adrive force mechanism accommodated in said distal housing part and beingslidably arranged in relation to the distal housing part, a container 22filled with medicament arranged within said proximal housing part, aholding member 50 for holding said drive force mechanism in a loadedstate and arranged to be axially moved in relation to the distal housingpart a predetermined distance towards a distal end of the device by theproximal housing part when said housing parts are moved towards eachother along the longitudinal axis of the device, an actuation member 56arranged to interact with said holding member for releasing the driveforce mechanism from its loaded state, wherein said holding member isarranged to be moved from a disengaged position in which the holdingmember is disengaged from the actuation member to an engaged position inwhich the holding member is engaged to the actuation member by movingsaid housing parts in relation to each other.

In the present invention, the proximal housing part 12 comprises aco-acting means 60 and the holding member 50 comprises a counterco-acting means 62 which interact together for moving the holding memberin relation to the distal housing part a predetermined distance towardsa distal end of the device from the disengaged position to the engagedposition. The actuation member 56 comprises connecting means (not shown)and the drive force mechanism comprises counter connecting means (notshown). Further, the holding member 50 comprises engagement means (notshown) and the actuation member 56 comprises counter engagement means(not shown) such that when the holding member is moved by the proximalhousing part 12 when said housing parts are moved towards each other,from a disengaged position in which the holding member is disengagedfrom the actuation member to an engaged position in which the holdingmember is engaged to the actuation member, such that the engagementmeans of the holding member 50 and the counter engagement means of theactuation member 56 interact together for engaging the connecting meansof the actuation member 56 to the counter connecting means of the driveforce mechanism.

In the present invention, the actuation member 56 comprises a touchablepart that protrudes from the distal housing part and wherein saidactuation member is resiliently arranged to said distal housing part 10such that the actuation member 56 in the disengaged position of theholding member 50 can be moved relative to the distal housing partwithout acting on said drive force mechanism.

In the present invention the container 22 is e.g. a multi-chambermedicament container and the multi-chamber can be mixed by moving saidhousing parts towards each other along the longitudinal axis of thedevice. Further, the engaged position of the holding member correspondsto a position of the multi-chamber, in which the multi-chamber is mixed.

In the FIGS. 1-7 is shown an exemplary embodiment of the presentinvention.

The housing in the exemplary embodiment, FIG. 1, comprises a distalhousing part 10 and a proximal housing part 12, wherein said proximalhousing part is arranged to accommodate a container 22 as amulti-chamber medicament container and whereby the multi-chambermedicament container can be mixed by moving said housing parts towardseach other along the longitudinal axis of the device, preferably byscrewing said housing parts. The outer surface of the proximal housingpart 12 comprises threads 14 arranged to cooperate with correspondingthreads 16 on the inner surface of the distal housing part 10. Theproximal end of the proximal housing part is further arranged with aneck portion 18, which neck portion 18 is arranged with attachment meansfor attaching a medicament delivery member (not shown) wherein themedicament delivery member is preferably an injection needle. It ishowever to be understood that other types of medicament delivery membersmay be employed such as mouth or nose pieces, nozzles, nebulizing unitsetc. The proximal housing part 12 is also arranged with turning members20 such as longitudinally extending wings, which facilitate the manualturning of the proximal housing part in relation to the distal housingpart.

In the exemplary embodiment, the multi-chamber medicament container 22is e.g. a dual chamber container designed with two compartments 24,wherein one compartment contains preferably the medicament in powderform and the other compartment contains preferably a diluent, FIG. 2.The two compartments are separated by a resilient, movable stopper 28,which stopper when moved, opens passages between the compartments formixing the medicament with the diluent. A distally arranged secondstopper 30 closes the distal end of the medicament container.

The drive force mechanism in the exemplary embodiment comprises a driveforce spring 34, an elongated plunger rod 32 and a drive member 40. Thedrive member 40 has a generally tubular shape, is coaxially arranged onthe plunger rod and is partially surrounding said plunger rod. Theelongated plunger rod 32 has a proximal end in contact with the distalstopper 30. Inside the plunger rod 32 is arranged the drive force spring34, between a proximal end wall 36 of the plunger rod 32 and a distalend wall 38 of the drive member 40, FIG. 2. The drive member 40comprises releasable means 44 and the plunger rod 32 comprises counterreleasable means 42 which interact together for releasably engaging theplunger rod to the drive member.

In the exemplary embodiment, the outer surface of the distal tubularpart of the drive member 40 comprises an annular ledge which is arrangedto abut the circumferential ledge on the inner surface of the distalhousing part when a part of the distal tubular part of the drive memberpasses through the aperture formed by the circumferential ledge on theinner surface of the distal housing part. The releasable means 44 of thedrive member 40 are radially flexing arms provided with inwardlyextending ledges 46 and the counter releasable means 42 of the plungerrod 32 is a groove on its circumferential outer surface, wherein theinwardly extending ledges 46 fit into said groove. Preferably saidlongitudinally extending and radially flexing arms are configured toexert a radial outwardly directed force. Each arm 44 is further arrangedwith an outwardly directed ledge 48.

The holding member 50 in the exemplary embodiment has a generallytubular shape and is coaxially arranged over the drive member 40. Theholding member is in a disengaged position when the holding member iscompletely surrounding the radially flexing arms i.e. the ledges 48 ofthe arms 44 are completely surrounded by the inner surface of theholding member 50. The holding member 50 is axially movable in relationto the distal housing part, preferably arranged to be axially moved inrelation to the distal housing part a predetermined distance towards adistal end of the device by the proximal housing part when said housingparts are moved towards each other. In other words, the holding member50 is slidably moved in relation to the distal housing part apredetermined distance towards a distal end of the device by theproximal housing part from the disengaged position to the engagedposition wherein the holding member partially surrounds the radiallyflexing arms i.e. the ledges 48 of the arms 44 are partially surroundedby the inner surface of the holding member 50. The drive member 40 isfurther arranged with outwardly extending bumps or protrusions 54 on itsouter circumferential surface for holding the holding member 50 inposition relative the drive member 40, preventing the holding member 50from sliding in relation to the drive member 40 when the holding memberis in the disengaged position.

The drive force mechanism is in a loaded state when the drive forcespring 34 is pre-tensioned within said plunger rod, when the drivemember 40 is engaged to the plunger rod 32 and when the holding member50 is either in the disengaged or engaged position.

The actuation member 56 is in the form of a sleeve, preferably as a pushbutton in the exemplary embodiment and comprises a touchable part thatprotrudes from the distal housing part 10. Preferably, a distal part ofthe actuation member protrudes from the distal end of the distal housingpart. The actuation member is preferably movable in relation to distalhousing part in a longitudinal direction along the longitudinal axis ofthe device. The actuation member 56 is provided with an inner sleeveextending along the longitudinal axis of the device and into which aportion of the distal tubular part of the drive member 40 fits.Preferably, there is a certain distance between the distal end wall ofthe drive member 40 and a transversal wall of the actuation member 56.The actuation member 56 is resiliently connected to the distal housingpart such that after each time the actuation member is biased it willrecoil. Thus, a resilient member 58 is arranged between the transversalwall of the actuation member 56 and the circumferential ledge on theinner surface of the distal housing part. Therefore, the actuationmember can be biased in relation to the distal housing part from anon-operating position in which the actuation member partially protrudesfrom the distal housing part to an operating position in which theactuation member is confined within the distal housing and will alwaysrecoil after being biased.

In the exemplary embodiment, the co-acting means 60 of the proximalhousing part 12 is a distal end annular surface of the proximal housingpart and the counter co-acting means 62 of the holding member is anannular ledge on the outer circumference of the holding member.

In the exemplary embodiment, the engagement means of the holding member50 are distally extending tongues (not shown) i.e. tongues extendingtowards the distal end of the device along the longitudinal axis of thedevice. The counter engagement means of the actuation member 56 areproximally extending flexible tongues (not shown) i.e. tongues extendingtowards the proximal end of the device along the longitudinal axis ofthe device. Preferably said proximally extending flexible tongues areextending from the inner sleeve of the actuation member 56 over thedistal tubular part of the drive member.

In the exemplary embodiment, the connecting means of the actuationmember 56 are radial inwardly extending protrusions (not shown) on theproximally extending flexible tongues of the actuation member 56 and thecounter connecting means of the drive force mechanism are recesses (notshown) on the distal outer surface of the drive member 40, wherein saidrecesses are configured to receive said radial inwardly extendingprotrusions.

The device of the exemplary embodiment is intended to function asfollows. When the device is delivered to a user the proximal housingpart 12 is extended in relation to the distal housing part 10, FIG. 1.First the user attaches a medicament delivery member (not shown) to theproximal neck portion 18 of the proximal housing part 12. The next stepis then to mix the medicament in the multi-chamber medicament container22. The user then turns the proximal housing part 12 in relation to thedistal housing part 10, whereby the proximal housing part is moved orretracted into the distal housing part. This relative movement of thetwo housing parts causes the plunger rod 32 to move in relation to themedicament container 22 such that its proximal end pushes the distalstopper 30 in the proximal direction. This in turn causes the resilientmovable proximal stopper 28 to move such that passages are openedbetween the two compartments and the mixing is performed, FIG. 4.

Before mixing the components within the container, the actuation member56 is in the non-operating position and it is disconnected from thedrive force mechanism. Further, the holding member 50 is in thedisengaged position. Preferably, the actuation member 56 is disconnectedfrom the drive member 40. More preferably, the radial inwardly extendingprotrusions on the proximally extending flexible tongues of theactuation member 56 are disconnected from the recesses on the distalouter surface of the drive member 40. The disengaged position of theholding member in the exemplary embodiment is characterized by theposition of the holding member 50 when it is disengaged from theactuation member 56 and when it is completely surrounding the radiallyflexing arms 44 of the drive member 40 such that the inwardly directedledge 46 of the arms 44 are held in the groove 42 of the plunger rod 32and thereby the drive force spring 34 is held pre-tensioned within theplunger rod 32, i.e. the drive force mechanism is in the loaded state.Preferably, the holding member 50 is disengaged from the actuationmember 56 when the engagement means of the holding member 50 aredisconnected or not abutting or non operable with the counter engagementmeans of the actuation member 56. More preferably, the holding member 50is disengaged from the actuation member 56 when the distally extendingtongues of the holding member 50 are disconnected or not abutting or notoperable with the proximally extending flexible tongues of the actuationmember 56. Further, when the holding member 50 is in the disengagedposition and the actuation member 56 is biased, the spring 58 iscompressed and the distance between the distal end wall of the drivemember 40 and the transversal wall of the actuation member 56 isovercome. When the actuation member is released from pressure or bias,the compressed spring recoils and thereby forces the actuation member tobe moved towards the distal end of the device. However, the holdingmember 50 is in the disengaged position and thus it is not possible toactivate the device prior to mixing.

When the mixing is about to be completed, the distal end annular surface60 of the proximal housing part 12 is moved into contact with theannular ledge 62 on the outer circumference of the holding member 50such that the holding member is moved from the disengaged position tothe engaged position in relation to the drive member 40. Preferably, theholding member 50 is axially moved towards the distal end of the devicealong the longitudinal axis of the device. Then, the holding member isheld fixed between the circumferential ledge on the inner surface of thedistal housing part and the distal annular ledge of the proximal housingpart. The engaged position of the holding member in the exemplaryembodiment is characterized by the position of the holding member 50when it is engaged to the actuation member 56 such that the distallyextending tongues of the holding member 50 slide over the proximallyextending flexible tongues of the actuation member 56 forcing theproximally extending flexible tongues to flex radially inwards such thatthe radially inward directed protrusions of the proximally extendingflexible tongues come into engagement with the recesses of the drivemember 40 and when the holding member is positioned in relation to thedrive member such that a part of the ledges 48 of the arms 44 protrudeout of the proximal end of the holding member 50, FIG. 5, i.e. theledges 48 of the arms 44 are partially surrounded by the inner surfaceof the holding member 50.

The next step is now to perform a dose delivery. The user then positionsthe proximal part of the device at the medicament delivery site. When aninjection needle is used, the device is pressed on a skin surface of thepatient, whereby a penetration of the needle is performed.

After this, the actuation member, i.e. the push button 56 is depressedor biased, FIG. 7. This causes the resilient member 58 to be compressed,the drive member 40 to be moved towards the proximal end of the devicetogether with the plunger rod 32 because of the connection between thedrive member and the plunger rod, until the ledges 48 of the arms 44have passed the proximal end of the holding member 50, while the holdingmember is held fixed to the distal end surface of the proximal housingpart 12. The arms 44 of the drive member 40 are thereby free to expandin the radial outward direction whereby the inwardly directed ledges 46move out of the groove 42 of the plunger rod 32. The latter is now freeto move in the proximal direction by the force of the drive spring 34,which causes the stoppers 28, 30 of the medicament container 22 to bemoved in the proximal direction, thereby expelling a dose of medicamentthrough the medicament delivery member, FIG. 7. The actuation member isheld within the distal housing part during the injection sequence due tothe engagement between the drive member and the actuation member. Also,due to the movement of the drive member towards the proximal end of thedevice, a gap is created between the annular ledge on the outer surfaceof the distal tubular part of the drive member and the circumferentialledge on the inner surface of the distal housing part.

At the end of the injection sequence, the distal end of the plunger rod32 passes the proximal end of the drive member 40. The arms 44 of thedrive member 40 are then free to move radially inwards inside theholding member 50 and due to the residual force of the drive spring 34,the drive member 40 and the actuation member 56 will be pushed in thedistal direction until the annular ledge on the outer surface of thedistal tubular part of the drive member hits the circumferential ledgeon the inner surface of the distal housing part. This contact providesan audible sound, like a click, as well as a tactile feeling of theactuation member, which indicates the end of delivery. The actuationmember is also recoiled. If the user is still depressing the actuationmember, the user will be provided with a tactile feedback that indicatesthe end of delivery.

When the medicament delivery operation has been completed, the devicemay be removed from the medicament delivery site and be discarded in asafe way.

It is to be understood that the embodiment described above and shown inthe drawings is to be regarded only as a non-limiting example of theinvention and that it may be modified in many ways within the scope ofthe patent claims.

The invention claimed is:
 1. A medicament delivery device, comprising: ahousing, comprising a proximal housing part and a distal housing partmovable relative each other; a drive force mechanism accommodated in thedistal housing part and comprising a counter-connecting device; acontainer filled with medicament within the proximal housing part; aholding member operably connected to the drive force mechanism forholding the drive force mechanism in a loaded state, wherein the holdingmember comprises a connecting device and an engagement device; and anactuation member arranged to interact with the holding member forreleasing the drive force mechanism from its loaded state, wherein theactuation member comprises a counter-engagement device; wherein theholding member is arranged to be moved by the proximal housing part whenthe proximal and distal housing parts are moved toward each other from adisengaged position, in which the holding member is disengaged from theactuation member, to an engaged position, in which the holding member isengaged to the actuation member, such that the engagement device and thecounter-engagement device interact for engaging the connecting device tothe counter-connecting device.
 2. The medicament delivery device ofclaim 1, wherein the proximal housing part comprises a co-acting deviceand the holding member comprises a counter-co-acting device thatinteract together for moving the holding member from the disengagedposition to the engaged position.
 3. The medicament delivery device ofclaim 2, wherein the co-acting device includes a distal-end annularsurface of the proximal housing part, and the counter co-acting deviceincludes an annular ledge on an outer circumference of the holdingmember.
 4. The medicament delivery device of claim 1, wherein theactuation member comprises a touchable part that protrudes from thedistal housing part, and the actuation member is resiliently arranged tothe distal housing part such that the actuation member in the disengagedposition of the holding member is movable relative to the distal housingpart without acting on the drive force mechanism.
 5. The medicamentdelivery device of claim 1, wherein the drive force mechanism comprisesa plunger rod, a drive force spring, and a drive member.
 6. Themedicament delivery device of claim 5, wherein the drive membercomprises a releasable device and the plunger rod comprises acounter-releasable device that interact together for releasably engagingthe plunger rod to the drive member.
 7. The medicament delivery deviceof claim 6, wherein the releasable device includes radially flexing armsprovided with inwardly extending ledges, the counter-releasable deviceincludes a groove on its circumferential outer surface, the inwardlyextending ledges fit into the groove, and the holding member completelysurrounds the radially flexing arms when the holding member is in thedisengaged position.
 8. The medicament delivery device of the claim 7,wherein the holding member is moved by the proximal housing part fromthe disengaged position to the engaged position, in which the holdingmember partially surrounds the radially flexing arms and is engaged tothe actuation member.
 9. The medicament delivery device of claim 1,wherein the engagement device includes distally extending tongues andthe counter-engagement device includes proximally extending flexibletongues.
 10. The medicament delivery device of claim 1, wherein theconnecting device includes radial inwardly extending protrusions on theproximally extending flexible tongues of the actuation member, and thecounter-connecting device includes recesses on a distal outer surface ofthe drive member, such that the recesses are configured to receive theradial inwardly extending protrusions.
 11. The medicament deliverydevice of claim 1, wherein the container is a multi-chamber medicamentcontainer, and materials in the multi-chamber are mixed by moving theproximal and distal housing parts toward each other.
 12. The medicamentdelivery device of claim 11, wherein the engaged position of the holdingmember corresponds to a position of the multi-chamber in which thematerials are mixed.